U8L3 Investigating Water Quality Lab Flashcards
What is the definition of biodiversity?
The variety of life within an ecosystem, including all plants and animals
What is the definition of eutrophication?
Excessive nutrients in a water body causing overgrowth of algae, plankton, and other microorganisms.
What is turbidity?
Turbidity is a measure of the relative clarity of the water.
How is turbidity measured?
Turbidity is measured using a disc with contrasting black and white sections, which is called a secchi disc. The disc is lowered into the water until the black and white sections cannot be clearly distinguished. The higher the depth measurement (usually feet and inches), the less turbid the water.
How does turbidity affect water?
Water that is highly turbid will absorb heat (see effects of temperature) and block sunlight. Underwater plants are dependent on sunlight for photosynthesis, so blocking the light causes these plants to die off. Many aquatic organisms depend on the plants for oxygen, food, and shelter.
How is temperature measured?
Temperature is measured in degrees F or C. In a body of water, temperatures will vary based on the depth of the sample.
How does the temperature affect water?
Aquatic life of various types have optimal temperatures for survival. Temperatures that are either too warm or too cold will cause loss of aquatic life and diversity. Temperature also affects the solubility of toxic chemicals and heavy metals. Many toxic chemicals and heavy metals will better dissolve in warmer water. Warmer temperatures also increase the metabolic rate of organisms. Increasing the metabolic rate of plants increases their need for oxygen for photosynthesis. Increasing the metabolic rate of other aquatic organisms can weaken them and leave them subject to parasites and disease.
What is pH?
pH is a measure of how acidic or basic (alkaline) the water is.
How is pH measured?
pH is cited as a figure between 0 and 14 defining how acidic or basic a body of water is along a logarithmic scale. The lower the number, the more acidic the water is. The higher the number, the more basic it is. A pH of 7 is considered neutral.
How does pH affect water?
At either extreme, aquatic organisms die. pH also affects the solubility and toxicity of chemicals and heavy metals in the water. Also, the solubility of phosphorus and nitrogen is affected by variations in pH, making these nutrients more available for plant
growth. This means that pH levels that promote phosphorus and nitrogen availability to plants can be part of a chain of effects leading to eutrophication.
What is eutrophication?
the process by which a body of water becomes enriched in dissolved nutrients (such as nitrogen and phosphates) that stimulate the growth of aquatic plant life like algae blooms. When the organic matter decays, the water is depleted of dissolved oxygen
What is dissolved oxygen?
Though oxygen is one of the atoms in a water molecule, this oxygen is not available for living aquatic animals. They need the oxygen molecule (O2) just like we do. Oxygen can be dissolved in water just like carbon dioxide is dissolved in soft drinks. You don’t see it (until you see the CO2 bubbles), but it is jostling around among the water molecules. Dissolved oxygen gets into the water primarily from the atmosphere, secondarily from groundwater. Faster flowing water will have higher levels of dissolved oxygen than stagnant water.
How is dissolved oxygen measured?
There are different testing methods for determining how much dissolved oxygen is in a water sample. Whichever test method is used, the final reading will be the milligrams of oxygen per liter. Dissolved oxygen in a waterway may measure in a range from 0 mg/l to 18 mg/l. The amount of dissolved oxygen in the water will be inversely related to the temperature. The warmer the water, the less dissolved oxygen it will contain.
How does dissolved oxygen affect water?
Dissolved oxygen is essential for aquatic life. Plants need dissolved oxygen for photosynthesis. Animals breathe the dissolved oxygen in the water, not the oxygen from water molecules. One result of eutrophication is bacteria from decaying organic matter consuming all of the dissolved oxygen, resulting in death of aquatic life.
